Construction unit



Nov. 7, 1939e NNI N Nw JUNIN Patented Nov. 7, 1939 .CONSTRUCTION UNIT Joseph E. Willetts, Pittsburgh, Pa.

Application May 6, 1936,'Serial No. '78,147

5 Claims.

This invention relates to improvements in construction members or units particularly adapted for use in the reinforcement of concrete and the like, although their uses are not to be limited thereto.

Concrete slab construction, as for examplethat employed in the formation of present day concrete roads or highways, generally employs reinforcement in the form of steel bars or mesh. Despite theuse of such reinforcement, cracking and failures in the road surface are constantly recurring, which damage is probably causedV by failure of the sub-grade with resultant loss of support to the overlying concrete.

The increasing traic on the highways, .particularly augmented by heavy trucks and trailers hauling freight loads, quickly deforms the weakened road surface, causing the formation of large and dangerous holes and breaks therein. This depreciation in the highways and roads has necessitated the yearly expenditure of large sums for repairs and replacements.

It is a prime object of my invention to provide for the reinforcement of Such concrete roads and other concrete slabs, whereby the applied loading will be distributed in all directions -to the slab, thus relieving unsupported areas and preventin their destruction under impact.

A further object is to provide a construction having extensive internal contact and bond with the concrete to continuously interlock or key the concrete against severance of the loaded areas from the main body of .the slab.

Additional objects are to provide asimple and economical structure whichmay be`readily-'fab ricated and applied.

In the drawing which illustrates a preferred embodiment of my invention:

Fig. 1 is a transverse sectional view of a standard concrete highway slab showing my invention applied thereto;

Fig. 2, a perspective View of a plurality of the construction units of my invention;

Fig. 3, an enlarged detail sectional View of a portion of Fig; 1, showing the manner of applying the unit to the concrete;

Fig. 4, a' similar enlarged sectional view, particularly illustrating the keying action of the unit;

Fig. 5,. ar detail perspective view showing one manner of assembling the unit;

Fig. 6, a view similar'to Fig. 5, showing an alternative manner of assembly; and

Fig. '7, a detail perspective view of a modied form of the invention.

Referring to the drawing, 2 designates generally a c'oncretehighway slab constructedv injac' cordance with-standard design upon a prepared and rolled sub-.grade 2a.` In forming the' subgrade, the earth is cut away to the proper width and rolledl and shapedin slightly rounded form,

slab, but as stated, this form of reinforcemente.

has not satisfactorily resisted the present day heavy traic and loading.V

To alleviate the difficulties encountered, I have Ulli) provided a new construction unit comprising'an open-work or mesh typeanged `reinforcement generally designatedk A, preferably formed of sheet steel and pre-,formed into said units. Each unit A includes lplural. series of crossedorinter'- secting members3 and 4 formed of fiati-sheets bent into substantially V-shape with downwardly and outwardly rdiverging longitudinal flangesy 5 of substantial depth, and having upper? central terminal edges preferably slightly 'flattened as shown atf6.

The members 3 and ll may be secured together in any suitable manner. For example, in Fig. 5, I haveshown the flanges 5 of the members lout away as at 'l at regular intervals to telescope over the members 3, said cut-awa'yportions however not extending into the edges 6, thereby providing ,t

3 and 4, together with the angiilarly-disposed bounding vor enclosing flanges 5l ofthe saidmernbers, providing forms or mold-like cavities'B for the reception of concrete., Duetoy the-,angularity of the flanges 5, they become downwardlycone Vergent limitingwallsfor the mold cavities B,

forming the latter of substantially invertedtruncated pyramidal form.

In forming the concrete slab 2, I prefer to first pour the concrete onto the sub-grade 2a toa depth indicated by the une a-a, or substantially equal to the vertical depth of the reinforcing units A, which units are then applied to the pour by insertion flatwise, with the edges 9 of the respective members 3 and 4 thereof downward. The flanges 5 or edges 6 of the unit members may be perforated as at I0, to allow for the escape of air trapped within the members as the unit settles downwardly in the concrete to rest by its edges 9 on the sub-grade 3 as shown.

The nished pour is then applied to provide the prescribed total depth of the slab 2, being finished off with the proper finishing tool which will impart the desired crown to the finished The masses of concrete disposed within the Vmold cavities B are effectively keyed or Ainter.- .locked against downward displacement, and due Ato theflatwise angular interposition of the metal Ifiangesl, a transverse load applied to the slab will bepartially transmitted laterally through the slab, thereby relieving the'downward strain on the loaded area.

Likewise, the distribution of load will minimize any centralized deflection an in unsupported area. .For example, assuming a failure of the sub-grade as indicated at Il in Fig. 4, a load applied vdirectly thereover will be laterally distributed to relieve the local portion of the slab, and together with the supporting action of the unit A per se, will prevent failure of the slab.

While the reinforcing means of my invention may be formed in one continuous mat or assembly, lI have shown the same comprised of individual units of proper proportions. Fork example, in constructing a highway slab twenty feet in width,- each unit A may be ten feet square, two of such units being employed per ten foot length of slab.

I also prefer to have the ends of the unit memibers 3 and 4 project on all sides of the unit whereby to join with like projecting portions of the next unit, as by overlapping contact l2, or any other suitable manner of connection. The lengths of the projecting end portions of members 3 and 4 are preferably such as to enclose a series of mold cavities B substantially like the cavities B for continuity of the'keying action Vthroughout the slab.

While the units A will accommodate themselves to the slight curvature of the sub-gradeZa, they may be ,preformed with a -proper curvature before being applied to the slab.

, Fig. 6 illustrates another manner of fabricating the units, whereby the members 3 are slightly depressed at spaced intervals along their top edges 6 as at I3, whereby to saddle the bridge portion 8 of the member 4 without projection, and vmaintaining the lower edges 9 of the members in the same plane.

As a further modification,` in Fig. '7 I have shown the lower edges of the members 3 and 4 formed with lateral marginal flanges 9a to afford added supporting effect.

While I have shown and described my new construction unit in connection with the reinforcing of concrete, it will be understood that the same may be advantageously employed as a building unit for spacing or supporting other layers of building or construction material.

I claim:

1. A concrete reinforcing unit for embedding in the concrete in spaced relation below the upper surface of the concrete including a plurality of spaced intersecting perforated members having downwardly inclined longitudinally extending v\flan, .g:es, the flanges of adjacent members forming h"al `mold cavity having downwardly converging side walls for receiving and supporting concrete therebetween.

2 A concrete reinforcing unit for embedding in the concrete in spaced relation below the upper surface of the concrete including a plurality of spaced intersecting members having downwardly inclined longitudinally extending flanges, said plane.

3. A construction unit of the character described for embedding in the concrete in spaced relation below the upper surface of the concrete including a series of metallic members each bent into V-shape with their apices flattened and widened to form concrete-supporting portions and having angularly related longitudinally eX- tending flanges, a second series of metallic members of similar contour, said members having spaced perforations, the flanges of one series. of members only being cut away for telescoping engagement with the members of the other series in intersecting relation, the edges of the anges of the members when assembled being disposed substantially in a common plane.

4. A road slaby including a lower portion of concrete, a metallic reinforcing unit embedded in said lower portion and including a plurality of intersecting members. vhaving vdownwardly inclined longitudinally extending diverging flanges terminating relatively far apart substantially in a common horizontal plane, the flanges of adjacent members forming mold cavities of pyramidal form for the retention of concrete therein, and a top portion of concrete above' the reinforcing uns. t -11 i 5. A road slab including a portion of concrete, a reinforcing unit embedded in said portion and terminating below thev top thereof and including a plurality of intersecting metallic members having downwardly inclined longitudinally extending diverging flanges terminating relatively far apart substantially in a same horizontal plane as the base of said portion, the anges of adjacent members forming mold cavities of pyramidal form forthe retention of concrete therein, portions of the concrete filling said metallic members betweenthe flanges said intersectingv members being perforated.

JOSEPH E.`WILLETTS. 

